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| United States Patent |
5,639,494
|
|
Grassin
, et al.
|
June 17, 1997
|
Pectinesterase in the treatment of fruit and vegetables
Abstract
A method to prepare a food containing a gel of a low-methoxylated pectin of
at least one fruit or vegetable is disclosed. The method comprises adding
pectin esterase to the fruit or vegetable or to the pulp thereof in an
amount effective to demethoxylate pectin, optionally adding calcium
chloride, and maintaining the fruit or vegetable or pulp under conditions
such that the pectin esterase converts high-methoxylated pectin of the
fruit or vegetable or pulp to low-methoxylated pectin and the
low-methoxylated pectin forms a gel. The fruit or vegetable or pulp is
then formulated to obtain the desired food containing the gel. The method
is used, for instance, to produce fruit and vegetable jams and jellies,
compotes, sauces and soups.
| Inventors:
|
Grassin; Catherine Marie Therese (Seclin, FR);
Fauquembergue; Pierre Clement Louis (Seclin, FR)
|
| Assignee:
|
Gist-brocades, N.V. (Ma Delft, NL)
|
| Appl. No.:
|
256856 |
| Filed:
|
December 5, 1994 |
| PCT Filed:
|
November 30, 1993
|
| PCT NO:
|
PCT/EP93/03379
|
| 371 Date:
|
December 5, 1994
|
| 102(e) Date:
|
December 5, 1994
|
| PCT PUB.NO.:
|
WO94/12055 |
| PCT PUB. Date:
|
June 9, 1994 |
Foreign Application Priority Data
| Current U.S. Class: |
426/50; 426/49; 426/52; 426/573; 426/615 |
| Intern'l Class: |
A23L 001/05 |
| Field of Search: |
426/50,49,52,615,616,573,574,577
|
References Cited
U.S. Patent Documents
| 2754214 | Jul., 1956 | Leo et al. | 426/50.
|
| 3615721 | Oct., 1971 | Silberman | 426/50.
|
| 3917867 | Nov., 1975 | Atkins et al. | 426/492.
|
| 4109017 | Aug., 1978 | Grampp et al. | 426/51.
|
| 4200694 | Apr., 1980 | Ishii et al. | 426/50.
|
| Foreign Patent Documents |
| 84317 | Sep., 1971 | DD | 426/50.
|
| 0025673 | Feb., 1984 | JP | 426/50.
|
| 9005463 | May., 1990 | WO | 426/50.
|
| 9100022 | Jan., 1991 | WO | 426/50.
|
Other References
Bock et al., Derwest Abstract 84-024248, PD202620, Sep. 1983.
Pilnik et al., "The Biochemistry of Fruits and their Products", Academic
Press (Hulme), vol. 1, 53-87 (1970).
|
Primary Examiner: Wong; Leslie
Attorney, Agent or Firm: Morrison & Foerster LLP
Claims
We claim:
1. A method to prepare a food containing a gel of low-methoxylated pectin
of at least one fruit or vegetable which method comprises:
adding pectin esterase to the fruit or vegetable or to the pulp thereof in
an amount effective to demethoxylate pectin;
maintaining said fruit or vegetable or pulp under conditions such that said
pectin esterase converts high-methoxylated pectin of said fruit or
vegetable or pulp to low-methoxylated pectin and said low-methoxylated
pectin forms a gel; and
formulating the fruit or vegetable or pulp to obtain the desired food
comprising said gel.
2. The method of claim 1 wherein said fruit or vegetable contains
high-methoxylated pectin.
3. The method of claim 1 wherein the fruit is apple, strawberry, orange,
peach, pear, apricots, raspberry or blackcurrant.
4. The method of claim 1 which is conducted in the absence of additional
gelling or thickening agents.
5. The method of claim 1 wherein the pectin esterase is of fungal origin.
6. The method of claim 5 wherein the fungus is Aspergillus.
7. The method of claim 1 wherein the pectin esterase is added in purified
form.
8. The method of claim 1 further comprising the step of adding calcium
chloride prior to allowing said low methoxylated pectin to form a gel.
9. The method of claim 1 wherein said food is selected from the group
consisting of jams, jellies, compotes, sauces and soups.
10. A process for converting a fruit or vegetable or pulp thereof
containing high-methoxylated pectin into a food product having increased
viscosity which process comprises:
adding pectin esterase to a liquid-containing composition comprising the
fruit or vegetable or pulp thereof in an amount effective to demethoxylate
high-methoxylated pectin;
maintaining said liquid-containing composition under conditions such that
said pectin esterase converts at least some of said high-methoxylated
pectin to pectin with a lower degree of methoxylation and said pectin with
a lower degree of methoxylation increases the viscosity of said
liquid-containing composition; and
formulating said liquid-containing composition to obtain the desired food
product having increased viscosity, which food product comprises said
fruit or vegetable or pulp thereof and said pectin with a lower degree of
methoxylation.
11. A process according to claim 10 wherein the fruit is apple, strawberry,
blackcurrent, orange, peach, pear, apricots or raspberry.
12. A process according to claim 10 wherein said pectin esterase is added
in an amount of between 50 and 500 PE units per kilogram of fruit or
vegetable or pulp.
13. A process according to claim 10 wherein said food product is selected
from the group consisting of jams, jellies, compotes, sauces and soups.
14. A process according to claim 10 wherein said food product is a filling
for a chocolate, cake or sweet.
15. A process according to claim 10 wherein after adding said pectin
esterase said liquid-containing composition is maintained under conditions
such that said pectin esterase converts high methoxylated pectin to pectin
with a lower degree of methoxylation for not more than about ten minutes.
16. The process according to claim 10 wherein said pectin esterase is
obtainable from a fungus which is a species of Aspergillus.
17. A process according to claim 10 for converting apples to applesauce
having increased viscosity, which process comprises
(a) adding to a liquid-containing composition consisting essentially of
prepared apples an amount of pectin esterase effective to lower the degree
of methoxylation of pectin contained in said apples wherein the apples
have been prepared by peeling and removal of the core, removing bad
apples, and crushing, chopping or slicing the remaining apples;
(b) maintaining said composition under conditions sufficient for the
demethoxylation activity of said pectin esterase to produce an increase in
the viscosity of said composition; and
(c) steam cooking the apples treated as set forth in (a) and finishing in a
process which comprises removing undesired particles, adding sugar and
canning.
18. The method of claim 17 comprising the additional step of placing the
treated apples of step (a) in a holding tank prior to the steam cooking
step of step (c).
Description
TECHNICAL FIELD
The present invention relates to the use of pectinesterase (E. C. 3.1.1.11)
in the preparation of food containing fruits or vegetables. Specifically,
the invention relates to the use of pectinesterase in the treatment of
fruit or vegetables that is in the demethoxylation of pectin. The treated
fruits or vegetables are then used in the preparation of jams, jellies,
compotes, sauces and soups. The present invention further discloses a
modification to the standard US apple sauce preparation process.
BACKGROUND OF THE INVENTION
Fruit and vegetable jams and jellies are normally prepared by cooking
protreated fruit and subsequent cooling. The pectin present in the fruit
gelates, thereby giving the jam or jelly its rheological characteristics.
The pectin is mainly responsible for this gel formation due to its
gelifying power. The gelifying potential of pectin is dependent on several
conditions, mainly:
dry substance content or brix,
pH of the fruit or vegetable,
concentration of pectin normally present,
degree of methylation of the pectin.
Pectins are major constituents of the cell walls of edible parts of fruits
and vegetables. The middle lamella which are situated between the cell
walls are mainly build up from protopectin which is the insoluble form of
pectin. Pectins are considered as intercellular adhesives and due to their
colloid nature they also have an important function in the waterregulation
of plants. Waterbinding capacity is greatly increased by the amount of
hydrophylic hydroxyl and carboxyl groups. The amount of pectin can be very
high. For example, lemon peels are reported to contain pectin upto 30% of
their dry weight, orange peels contain from 15-20% and apple peels about
10% (Norz, K., 1985. Zucker und Susswaren Wirtschaft 38 5-6).
From a chemical point of view pectin consist of methoxylated
polygalacturonic acid residues. Pectins are classified in differemt
categories based on the degree of esterification and the degree of
polymerisation.
On the basis of the degree of esterification pectins are divided into two
groups:
1) high-methoxylated pectins with a degree of esterification higher than
50%, and
2) low-methoxylated pectins having a degree of esterification lower than
50%.
Both of these groups are capable of forming gels, however these gels differ
in the mechanism by which they are formed. The high-methoxylated pectins
form gels based on dehydration and electrical neutralisation of colloidal
pectin-agglomerates. Gelation is stimulated if the pH is about 3
(dependent on the fruit or vegetable in question) and sugar, needed for
the dewatering, is present in more than 60% dry weight. Depending on the
fruit, in practice, this often means that both sugar and high-methoxylated
pectin have to be added to obtain the classical high sugar content jams.
Structure forming interactions in the high-methoxylated pectin containing
gels is based on hydrogen bond formation.
The low-methoxylated pectins are capable of forming gels with calcium ions
or other divalent cations only. Gel formation with low-methoxylated
pectins is based on ionic interactions. Calcium ions are naturally present
in for example apples. No sugars have to be added in order to obtain
suitable gelling properties. The amount of sugar and the pH in this case
only influence the speed and temperature of gelifying. Low-methoxylated
pectins are therefore perfectly suited for the preparation of low sugar
content jams and jellies.
In practice pectin from fruits and vegetables generally has a high degree
of methoxylation which necessitates the addition of large amounts of
sugars to obtain suitable rheological characteristics. Furthermore, the
degree of methoxylation varies with the time elapsed between the
harvesting and the processing of the vegetables or fruit. This leads to a
difference in the viscosity of the produced jams and jellies if the
processing conditions are kept constant.
SUMMARY OF THE INVENTION
The present invention discloses the use of pectinesterase in the
preparation of food containing fruits or vegetables. Specifically, the
invention discloses the use of pectinesterase in the treatment of fruit or
vegetables that is in the demethoxylation of pectin. The treated fruits or
vegetables are then used in the preparation of jams, jellies, compotes,
sauces and soups.
The pectinesterase is used to demethoxylate the high-methoxylated pectins
to obtain low-methoxylated pectins. The pectins obtained in this manner
show calcium dependent gelation. This gel formation does not require the
addition of sugars.
The present invention discloses jams and jellies obtained after the use of
pectinesterase.
Furthermore, the present invention discloses a method for treating the
crude fruit products with pectinesterase.
The present invention also discloses a process for obtaining apple sauce
comprising the use of pectinesterase. Furthermore, the present invention
discloses how the characteristics of the apple sauce are improved using
pectinesterase in the standard US apple sauce preparation process. The
invention also discloses how this standard process can be improved by a
slight alteration in the process i.e. the introduction of a holding tank
at a certain process stage.
BRIEF DESCRIPTION OF THE FIGURES
FIG. 1 is a schematic presentation of the apple sauce preparation process
as used in the USA. The holding tanks 1) and 2) are suggested
modifications to the standard process.
DESCRIPTION OF THE INVENTION
The present invention discloses the use of pectinesterase in the
preparation of food containing fruit or vegetables. The present invention
discloses a method for preparing food containing fruit or vegetables
comprising the addition of pectinesterase to the fruit or vegetable or to
the pulp thereof to demethoxylate the pectin, and optionally, the addition
of calciumchloride allowing the mixture to form a gel and further
formulating the so-treated fruit or vegetable to obtain the desired food.
Preferably, the fruit or vegetable is selected from the group of fruits or
vegetables containing high-methoxylated pectins.
Specifically, the invention is used in the preparation of fruit and
vegetable jams and jellies, compotes, sauces and soups.
The inventors demonstrate that it is possible to treat crude fruit or
vegetable products with pectinesterase, that due to this treatment the
degree of methoxylation of the pectin is lowered and that the resulting
pectin gelifies with the calcium that is present in the fruit or
vegetable. If the gelling is not complete it is possible to add high
methoxylated pectin before enzyme addition or to add low-methoxylated
pectin.
This process works well with fruits or vegetables which contain
high-methoxylated pectins, such as apple, strawberry, blackcurrant,
orange, peach, pear, apricots and raspberry.
In the present invention both-strawberries and apples were used. The first
since it is a popular jam species and the second for its high content of
high-methoxylated pectins.
Pectinesterases suitable for performing this process can be obtained from
different sources. The pectinesterase of the present invention can be any
pectiaesterase from plants, bacteria or fungi, suitable for the
degradation of high-methoxylated pectin. Preferably, the pectinesterase is
from fungal origin. More preferably, the pectinesterase is obtained from
Aspergilli, especially preferred is the use of pectinesterase obtained
from Aspergillus niger.
In a most preferred embodiment purified pectinesterase is used. This
purification can be performed in different ways.
The crude enzyme may be purified for example by liquid chromatography (ion
exchange, gel filtration, affinity) (Ishii et el., 1980. Deutsches
Patentamt Auslegeschrift 2843351) or by selective inhibition of the pectin
depolymerases (pH shock, heat shock, chemical inhibitors, chemical or
organic solvents extraction) (Smythe C. et el., 1952. U.S. Pat. No.
2,599,531) Another source for obtaining purified pectinesterase as defined
for the present application is pectinesterase obtained by recombinant DNA
technology. An example of the use of recombinant DNA technology is the
expression cloning of the Aspergillus niger pectinesterase. The cDNA
sequence of this gene has been reported (Khanh et el. Nucl. Acids Res. 18
4262 (1990)). As expression host Aspergillus niger could be used. However,
in view of the possible contamination of the pectinesterase with
polygalacturonase, pectin lyase and other pectin depolymerases it may be
preferable to use a heterologous host organism for producing the
pectinesterase.
Suitable host organisms include bacteria and fungi. Preferred species are
Bacilli, Escherichia, Saccharomyces, Kluyveromyces and Aspergilli.
The pectinesterase treatment of the present invention can be performed on
entire fruits or vegetables, it can also be performed on presliced or
ground fruits or vegetables. The pectinesterase treatment of fruit or
vegetables is performed as follows;
pectinesterase is added to the crude or pretreated fruit or vegetable, the
amount may vary as long a clear effect on the viscosity of the final
product is detectable. Effective amounts, as shown for example in Examples
of the present invention range from about 30-500 PE units per kg. These
values merely serve as indications. It is understood that the effect of
pectinesterase does not only depend on the amount of enzyme added but also
on the time the enzyme performs its activity.
also required for obtaining the desired gels is the addition of cations. In
the present description this is illustrated by the use of calciumchloride.
Again calcium ions are to added in effective amounts. In Example 1 this is
250 ppm in the form of calciumchloride.
the temperature of the reaction is not critical and may range from
10.degree.-70.degree. C.
reaction time again is not critical. Under application conditions it is
desirable to keep reaction times low, for economical reasons. It is shown
that a reaction time of about 10 minutes leads to a considerable
improvement in the quality of apple sauce.
finally the reaction is stopped by heat inactivation of the enzyme. This
inactivation may coincide with the sterilisation of the product before
canning or packaging.
The treatment leads to an increased firmness and viscosity of the product.
After enzymatic treatment the fruits or vegetables can be added to dairy,
bakery or confectionary products such as yoghurts, ice creams or desserts.
The products can also be used as jams or jellies or fillings for
chocolates, cakes or sweets. Another use is in the coating of other food
products. By treating entire fruits or vegetables prior to freezing the
firmness of the fruits or vegetables after defreezing is increased. The
pectinesterase treatment can also be used to improve the firmness of the
entire fruits or vegetables. Pectinesterase treatment before blanching or
cooking can be used to retard or prevent softening of the fruit or
vegetable.
Retarding vegetable softening by cold alkaline pectin deesterification
before cooking has been reported (van Buren and Pitifer. J.Food Sci. 57
1022-1023 (1992)) and it is to be expected that enzymatic deesterification
also retards the indicated softening.
Apart from the direct uses of the treated fruit or vegetables as mentioned
above, the application of the low-methoxylated pectins diminishes or
abolishes the required use of sugars or other gelifying agents. After
treatment of high-methoxylated pectin containing fruits or vegetables with
pectinesterase the use of texturing agents such as exogenous pectin or of
gelling or thickening agents obtainable from higher plants, seaweeds,
animals or microorganisms (such as alginate or carageenan) can be largely
diminished.
A further advantage of the use of gels from low-methoxylated pectins is
that in comparison with high-methoxylated pectin gels the gels are
irreversible. This means that heating and subsequent cooling does not
destroy the gel. This heating and cooling is responsible for the
well-known increase in fluidity of the jams upon storage. To the expert in
is clear from the above that pectinesterase may be used in any foodstuff
where low-methoxylated pectins normally are applied. Examples of such
foodstuffs are apart form the mentioned jams and jellies all kinds of
fruit fillings, glazes and aspics. Instead of using low-methoxylated
pectin as such the low-methoxylated pectin can be obtained by in situ
formation from high-methoxylated pectins through the action of
pectinesterase. In principle the formation of the (partially) demethylated
pectin can be performed during any phase of the manufacturing process.
The present invention is illustrated by treatment of apples and
strawberries with pectinesterase and it is shown that the viscosity is
considerably increased after using the demethoxylating enzyme this effect
is even more pronounced upon the addition of calciumchloride. The
gelfirmness, measuresed as grams of counterpressure using a Stevens
Texture Analyser, increases upon treatment with pectinesterase. By adding
calciumchloride the firmness can even be increased more.
In other examples it is shown that under normal processing conditions the
viscosity of apple sauce is increased following treatment with
pectinesterase.
Use of pectinesterase leads to a better consistency as measured by the flow
ring method. Consistency is an important measure for the quality of apple
sauce. Other improvements related to the use of pectinesterase in apple
sauce preparation process are, a better mouthfeel and the absence of free
run juice.
The results of the industrial trials indicate that pectinesterase can be
used with its profitable effect without any alterations to the present
production process.
The incorporation of pectinesterase in the present US standard apple sauce
production process, without altering the process as such, leads to a very
short reaction time for the pectinesterase (80-120 seconds). Even with
this short reaction time pectinesterase gives clearly favorable effects on
the product quality. This prompted the inventors to study the effect of a
longer reaction time of the pectinesterase on the quality of the apple
sauce. Bench-scale experiments indicated that increase of the reaction
time to about 10 minutes increases the product quality even more.
Therefore, as another aspect the present invention discloses an altered
production process for the preparation of apple sauce. The alteration
consists of the introduction of a holding tank in the apple sauce
preparation process in order to increase the effective reaction time of
pectinesterase. It is suggested to keep the holding tanks under nitrogen
and ad room temperature if positioned at position 1) at position 2) the
temperature is preferably about 60.degree. C. The prefered holding time is
about 10 minutes and the volume of the tank should be chosen accordingly.
The present invention therefore discloses a process for preparing apple
sauce whrein the following steps are performed;
1) washing of apples,
2) sorting to remove bad apples,
3) peeling and removal of the core,
4) sorting to remove bad apples,
5) crushing, chopping or slicing of the apples,
6) hopping of the apples to the cooker,
7) steam cooking of the apples,
8) finishing i.e. removing of stamens, peels, seed and other undesired
particles,
9) addition of sugar,
10) canning,
characterized in that pectinesterase is added to the apples after crushing,
chopping of slicing of the apples.
In an improved version of this process a holding tank is addded after the
enzyme addition step and before the steam cooking step. The holding tanks
are preferably kept under nitrogen and the holding time, which varies with
the temperature, the amount of enzyme added and the desired apple sauce
consistancy.
The use of pectinesterase in the apple sauce process allows for the
product/on of top (constant) quality apple sauce during the whole season.
As mentioned before the degree of methoxylating changes with the time
after harvesting. The quality of the apple sauce using a standard process
thus depends on the freshness of the fruits used in the process. Enzymatic
demethoxylation leads to a constant and reproducible degree of
methoxylation and thus to a constant quality gel or apple sauce.
EXAMPLES
Experimental
Assay of pectin esterase activity
One PE unit as used in the present specification is defined as the amount
of enzyme which hydrolizes one microequivalent carboxymethyl in one minute
under reaction conditions at 30.degree. C. and pH=4.5. The substrate is
Apple pectin Ruban Brun 0.5% with a methylation degree of over 70% in
water.
One PE Unit=0.98 PE International Unit. Experiments are performed with
pectinesterase which is preferably free from pectin lyase and
polygalacturonase activities. Purification can be performed by standard
methods as mentioned in the description.
EXAMPLE 1
Pectinesterase treatment of fruit and influence on firmness
In the present experiments strawberries and apples were used.
Strawberries, without the green pans, were ground using a Waring blender
for 30 seconds at low speed.
Apples; a blend of 33% Golden Delicious, 33% Red Delicious and 33% Granny
Smith were first cut into small pieces, without the stem. Subsequently the
apples were strained with the aid of a Roto shredder fixed on a Hobart
mixer (model N-50G, speed 2). The mass was then grinded, for 30 seconds
(high speed), using a Waring blender (model 32BLB0).
The fruit pulp (strawberries and apples were treated in the same manner)
was devided into six portions of 300 grams and each portion was poured
into an erlenmeyer flask.
Pectinesterase (240 PE units/g) was added to the pulp in two different
concentrations. As can be seen in Table 1, flasks 1 and 2 were blanks.
Flasks 3 and 4 contained 250 PE units/kg and flasks 5 and 6 contained 500
PE units/kg.
The flasks were placed in a waterbath (50.degree. C.) and stirred using a
magnetic stirrer. After one hour, calciumchloride was added to flasks 2, 4
and 6 and enzyme activity was stopped by placing all erlenmeyers in a
boiling waterbath for 2.5 min.
Finally, the hot pulp was poured into plastic cups (300 ml) and left to
stand for 24 hours at room temperature.
Firmness of the jellies was measured with the aid of a Stevens Texture
Analyser. Thereto a cylindrical plunger (TA4 1,5 inch) is brought into the
gel at a constant speed (0.5 mm/s). Firmness is defined as the force
required (in g) to penetrate the gel for a specified depth (5 mm).
Duplicate measurements were performed. Results are shown in Table 1.
TABLE 1
______________________________________
Gelfirmness in grams counterpressure for penetration of 5 mm.
Flask Strawberry Apple
______________________________________
1 Blank pulp 13 45
2 Blank pulp + 250 ppm CaCl.sub.2
13 45
3 Pulp + 250 PE u/kg 73 121
4 Pulp + 250 PE u/kg 56 250
+ 250 ppm CaCl.sub.2
5 Pulp + 500 PE u/kg 126 144
6 Pulp + 500 PE u/kg 117 249
+ 250 ppm CaCl.sub.2
______________________________________
The low firmness of flasks 1 and 2 indicates that gelification has
occurred.
Flask 3 shows that gelification takes place in both apple and strawberries
after addition of pectinesterase. Higher PE concentrations lead to
increased firmness (flask 5).
The influence of calcium on gelification clearly depends on the type of
fruit. The relatively low calcium concentration of apples, apparently
inhibits a quick gelification of the high concentration of demethylated
pectin. Addition of calcium then increases the gel strength and the rate
of gelification.
In strawberries the calcium concentration is relatively high, in
combination with a low pectin concentration the addition of calcium
results in a non-optimal calcium pectin ratio. This leads to a lower gel
strength.
EXAMPLE 2
Influence of pectinesterase treatment on viscosity of apple sauce under
large-scale processing conditions
In a typical large scale (3-5 tons) process the apples (Golden delicious)
are washed and ground. The temperature of this pulp is brought to
90.degree. C. by addition of fresh pulp to pulp kept at 94.degree. C. in a
ratio of 1:9 (the so-called Hot-break process). The pulp is kept at
90.degree. C. for 10 to 15 min before further processing.
Rapidase.TM. 9236 was added during the grinding at 150 g/ton and at 300
g/ton. Viscosity was measured by taking samples at different times and
cooling these samples to a standard temperature. Subsequently, these
samples were applied on a plate having a fixed inclination and the
distance travelled by the front of the pulp was measured after 1 or 2
minutes. The distance is a measure for the viscosity of the sample.
Results are shown in Table 2.
TABLE 2
______________________________________
Dose 150 g/ton 300 g/ton
Rapidase 9236
Temp. of 33.degree. C.
21.degree. C.
21.degree. C.
measurement
distance (mm) measured after
1 min. 1 min. 2 min.
1 min. 2 min.
______________________________________
Time of
measurement
after start
of PE addition
0 40 34 38 29 32
20 35 30 34 30 31
25 30 27 30 25 28
30 30 26 29 27 29
35 30 25 30 28 30
40 31 26 30 29 31
45 33 27 31 30 31
55 34 30 34 28 30
______________________________________
It can be calculated that the pulp was fully mixed with enzyme between 25
and 40 minutes. After and before these times the pulp was increasing
respectively, decreasing in amount of pectinesterase.
It can be concluded that viscosity increases due to pectinesterase
treatment under processing conditions. With 300 g/ton the increase in
viscosity was less then expected probably due to an overdosage of
pectinesterase with a concurrent lack of a sufficient amount of calcium.
EXAMPLE 3
Use of pectinesterase in an industrial process for production of apple
sauce
Enzyme preparation
In the present example pectinesterase from Aspergillus was used the enzyme
had an activity of 260 PE units/g.
Viscosity measurement
Viscosity measurement was performed using the flow ring (via flow) as
recommended by the USDA (United Sates Department of Agriculture).
Free run juice measurement
Free run juice was estimated visually. Quantities are indicated as follows:
+++a lot of free run juice
++medium amount of free run juice
+small amount of free run juice
-no free run juice
Mouthfeel test
The mouthfeel is graded by tasting. The following gradations are given:
poor taste
medium taste
good taste
very good taste
Description of the industrial apple sauce preparation process
Industrial apple sauce preparation is performed by the following processing
steps. The process described is the one normally used in the USA. This
process differs from the one used in Europe. The process is schematically
presented in FIG. 1.
Description of the process for apple sauce preparation in the USA
The process for apple sauce preparation comprises the following steps:
1) washing of apples
2) 1st sorting to remove bad apples
3) peeling and removal of the core
4) 2nd sorting to remove bad apples
5) crushing )
chopping ) different types of crushers
slicing )
6) hopper conveyor--conveyor to cooker
7) steam cooker--pulp heating to 93.degree.-94.degree. C.
8) finisher--removing of stamens, peels, seed and other undesired particles
9) bulking tank for sugar addition
10) canning line
Experiments
Three trials were performed at industrial scale. Pectinesterase was added
during transport of the sliced apples on the conveyor to the cooker.
Effective reaction time for the pectinesterase was therefore very short,
80-120 seconds. The temperature during the reaction on the conveyor was
60.degree. C. As mentioned before the mixture was heated by mixing with a
mixture of 93.degree.-94.degree. C. in a ratio of 1:9.
I. Contact time enzyme (max): 80 seconds.
Medium quality of apples, chopper: coarse paticles.
Enzyme 1200 g/ton apples.
Temperature 60.degree. C. at the place of addition.
______________________________________
Average Free run
consistancy
juice Mouthfeel
______________________________________
No enzyme 6.37 ++ ND
(before test)
With enzyme 6.01 + ND
No enzyme 7.04 +++ ND
(end of trial)
______________________________________
II. Contact time enzyme (max): 120 seconds.
Good quality of apples, chopper: small paticles.
Enzyme 1000 g/ton apples.
Temperature 60.degree. C. at the place of addition.
______________________________________
Average Free run
consistancy
juice Mouthfeel
______________________________________
No enzyme 5.9 - good
(before test)
With enzyme 5.4 - very good
No enzyme 5.9 - good
(end of trial)
______________________________________
III. Contact time enzyme (max): 120 seconds.
Good quality of apples, chopper: small paticles.
Enzyme 600 g/ton apples.
Temperature 60.degree. C. at the place of addition.
______________________________________
Average Free run
consistancy
juice Mouthfeel
______________________________________
No enzyme 6.26 ++ good
(before test)
With enzyme 5.75 - very good
No enzyme 6.32 ++ good
(end of trial)
______________________________________
It can be seen that through the addition of pectinesterase, without any
alterations to the apple sauce production process, the taste of the apple
sauce can be improved.
The criterium of consistancy is the most important for grading different
apple sauce preparations, it is related directly to the level and quality
of pectine in the apple. The industrial trials show an improvement of the
consistancy of the apple sauce after the use of pectinesterase.
In addition to the increase in consistancy an improvement of mouthfeel was
observed. Furthermore, the absence of free run juice is another sign of
increased quality of the apple sauce upon usage of pectinesterase.
The difference between the starting values is due to the fact that the
measurements have been performed at three different production facilities,
the apples were not the same brand and possibly from a different season.
EXAMPLE 4
Effect of pectinesterase on consistancy at different dosage
One gallon can of apple sauce was recovered from the canning line (Example
3, second trial) before cooling and at a temperature of
65.degree.-70.degree. C.
Four trials have been performed on 500 gram samples of apple sauce. The
trials consisted in the addition of different amounts of pectinesterase.
The mixtures were kept at 60.degree. C. for 10 minutes, subsequently the
temperature was raised to 92.degree. C. in a microwave oven. The
consistancy and the amount of free run juice were measured as described in
Example 3.
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Trial dosage consistancy
free run juice
______________________________________
1 control 5.70 +
2 200 g/ton 5.0 -
3 400 g/ton 4.85 -
4 600 g/ton 4.50 -
______________________________________
The results indicate that the quality of the apple sauce is further
improved, as evidenced by the consistancy and the amount cf free run
juice, by increasing the reaction time and concentration of the
pectinesterase.
Values below 5.5 can easily be reached and this value is considered to be
of importance in pricing of the product.
EXAMPLE 5
Effect of oectinesterase on consistancy at different temperatures
The apple sauce was recovered from the canning line as described in the
previous example. The apple sauce (500 gram samples) was heated to the
indicated temperatures and pectinesterase was added in an amount of 400
g/ton. The samples were left to cool. Consistancy, free run juice and
mouthfeel were determined as described in Example 3.
______________________________________
Trial
temperature consistancy
free run juice
mouthfeel
______________________________________
1 control 5.70 + good
2 82.degree. C.
5.45 - good
3 75.degree. C.
5.30 - very good
4 70.degree. C.
5.0 - very good
5 65.degree. C.
gel - --
6 60.degree. C.
gel - --
______________________________________
The results indicate that the consistancy, free run juice and mouthfeel
improve upon using pectinesterase. This effect is temperature dependent as
can be expected for enzyme activities.
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